Fuel injection pump for diesel engines



July 7, 1964 TOSHIO UMEZAWA FUEL AINJECTION PUMP FOR DIESEL. ENGINESFiled June 5, 1965 United States Patent O 3,139 830 FUEL INJECTION PUMPFOR DIESEL ENGINES Toshio Umezawa, 478-8 Oaza Tobushi, Ibaragi-shi,Osaka, Japan Filed June 5, 1963, Ser. No. 295,575 3 Claims. (Cl. 103-42)The present invention relates to fuel injection pumps for dieselengines.

This application is a continuation-in-part of my earlier application,Serial No. 38,230 filed June 23, 1960 and now abandoned.

In conventional types of fuel injection pumps, there is provided a fuelsuction valve wherein dust or dirt may be caught between the seat andthe valve element rendering the fuel injection pump inoperative.

The present invention is intended to overcome such diiculty byeliminating the use of suction valves in fuel injection pumps. For thispurpose, the present invention provides a fuel injection pump for adiesel engine having a barrel formed with a suction aperture so thatfuel may be drawn into the barrel as the plunger moves to open saidsuction aperture. According to a further feature of the presentinvention, a control valve is provided through which excess oil isreturned to a chamber provided on the suction side of the pump for thepurpose of reducing pressure variations due to the excess oil returned.

The present invention is also advantageous in that it provides a fuelinjection pump for a diesel engine which is simple in construction,economical in manufacture, and easy in handling.

Among the various features of the invention is the arrangement of excessfuel passages and the chambers which are provided for avoiding thetransmission of pressure waves throughout the apparatus;

More particularly, as will be shown in greater detail hereinafter, thereis provided a fuel delivery passageway extending from a bore in which acontrol rod is provided, there being further provided an excess fuelpassageway extending perpendicularly away from the fuel deliverypassageway and communicating with a control chamber in which is locateda control valve as will be described. From this latter chamber extends afurther passageway which is arranged in parallel with the fuel deliverypassageway and which opens into a chamber having a crosssection andvolumetric capacity such that the pressure of the excess fuel is abated.From the latter said chamber an inclined passageway leads to a fuelinlet passageway communicating at right angles with the bore of theaforesaid rod.

Other objects, features and advantages will become apparent from thefollowing detailed description, reference being had to the accompanyingdrawing wherein the sole figure shows, in section, a preferredembodiment of the invention.

In the drawing which is a cross-section of a fuel injection pumpaccording to the present invention, reference numeral 1 designates abody or casing of the fuel injection pump and numeral 2 a barrel in thecasing having an aperture or freely open passageway 3 for fuel suction.Numeral 4 designates a threaded retainer for holding the barrel 2 inplace within the pump casing 1 through the intermediary of packings 5and 6. A plunger 7 is disposed for compression and suction strokes inthe barrel ICC 2 and is provided with a collar 10. A coil spring 8 isprovided to act upon the plunger 7 through a spring seat 9 restingagainst the collar 10 of the plunger 7.

Also provided is a fuel delivery valve 11 which in turn is provided witha valve seat member 12 and a valve spring 13. A threaded member 14 isprovided for holding the seat member 12 in place on the valve casing. Asshown, the delivery valve 11 with the spring 13 is accommodated in thevalve seat member 12, which is mounted on the valve body 1 by thethreaded member 14. A fuel oil delivery passageway 15 is provided in thevalve body for communicating the fuel delivery valve 11 with a boreformed in the barrel and in which the plunger 7 operates.

Numeral 16 designates an excess oil control valve carrying a valvespring 17. The control valve 16 is provided as shown with a control rod18 having a threaded portion 21. A control rod holder 19 has aninternally threaded portion to engage with the threaded portion 21 ofthe control rod to hold the latter in an adjustable manner. A controlvalve chamber 22 is defined in the pump casing 1 around the controlvalve body 16, which is mounted on the control rod with the spring 17arranged therebetween as illustrated. The control rod holder 19 isthreadably fitted in the control valve chamber 22 with a packing 20interposed between a shouldered portion of the control rod holder 19 andan adjacent portion of the pump casing 1. An excess fuel oil passage-Way 23 extends perpendicular from passageway 15 to communicate the oilpassageway 15 as described above with the control valve 16.

Provided in the pump body 1 is a part of a chamber 24 for reducingpressure variations in communication with the suction aperture 3 formedin the barrel 2 through an inclined oil passageway 25 formed in the pumpbody 1. A return oil passageway 26, parallel with passageway 15,connects the control valve chamber 22 with the pressure variationreducing chamber 24.

Reference numeral 27 designates a base for mounting the fuel injectionpump thereon and having formed therein the remainder of the pressurevariation reducing chamber as indicated at 28. The pump base 27 has athreaded portion or fuel inlet passageway 29 for receiving a fuelsuction tube (not shown) in communication with the pressure variationreducing chamber 28.

Also provided in the pump base 27 is a bore 34 in which a slider 32 ismovable. The slider 32 carries a cam follower roller 3) mounted on a pin31 carried by the slider 32. The entire slider assembly is tted in thebore 34 in the pump base as shown. A stud 33 is provided on the pumpbase 27 to hold the slider 32 against rotation. A fuel cam 35 isarranged to cooperate with the follower roller 30.

In operation, as the fuel cam 35 rotates, the cam follower roller 3l) isactuated by the raised portion of the cam to advance the plunger 7through the intermediary of the slider 32 so that the suction aperture 3in the barrel 2 is closed. Continued advance of the plunger 7 acts tocompress the fuel oil conned in the delivery oil passageway 15 and theexcess oil passageway 23 to drive the delivery valve 11 open thereby tofeed oil to the fuel injection valve, not shown.

The control rod 18 is rotated by means of a speed governor, not shown,to move slightly upward due to threaded formation 21 on the control rod,thereby releasing the control valve 16. As a result, the fuel oilpressure in the delivery oil passageway and the excess oil passageway23, acting on the control valve 16, causes the valve to open to allow anexcess of fuel oil to flow into the control valve chamber 22 and furtherthrough the return oil passageway 26, perpendicularly connected tochamber 22,

back into the pressure variation reducing chamber 24-28 coaxial withpassageway 26 and at least several times greater in cross-section ordiameter than the same. Since the pressure variation reducing chamber24-28 has a cross-section at least several times greater than that ofpassageways 3 and 23 and a volumetric capacity far larger than thevolume of the excess oil returned, the pressure of the latter is reducedand fuel is delivered at reduced pressure to the base on which plunger 7slides.

With further continued rotation of the fuel cam 35, the plunger 7 isretracted by the force of the spring 8 through the spring seat 9 carriedon the plunger 7 to open the suction aperture 3 in the barrel 2 to allowfuel oil to be drawn into the barrel.

It will be appreciated that, according to the present invention, a fuelinjection pump is provided which avoids the need for a suction valve,and which is thus simple in construction, and economical in manufacturewith the fuel oil pressure around the suction aperture in the barrel 2remaining substantially at a predetermined level by the provision of apressure variation reducing chamber irrespective of the pressure of theexcess oil being returned.

Having fully described one embodiment of the invenltion, it will beevident that various changes in the construction and arrangement ofparts may be made without exceeding the scope of the invention.

What is claimed is:

1. A fuel injection pump for a diesel engine comprising a pump body, abarrel supported in said body, said barrel being provided with a bore, aplunger slidably supported in said bore for providing suction andcompression strokes in said bore, a freely open passageway beingprovided in the wall of said barrel at a location at which the plungerpasses beyond said passageway during said suction stroke Vto open saidpassageway while during said compression stroke the plunger closes saidpassageway, said passage- Way being in communication with said bore forpermitting fuel to ow into said bore during the suction Stroke of saidplunger, said pump body being provided with a fuel delivery passagewaywhich extends from said bore, valve means in the fuel deliverypassageway for controlling discharge of fuel from said fuel deliverypassageway, said plunger, during said compression stroke, exertingpressure on fuel in said bore and said fuel delivery passage to opensaid valve means to permit discharge of said fuel from said fueldelivery passageway, said body being provided with an excess fuelpassageway coupled to said fuel delivery passageway and with a chamberin communication with said excess fuel passageway to permit excess fuelin said fuel delivery passageway to be delivered to said chamber, saidbody being provided with a fuel inlet passageway opening into saidchamber, said chamber being of substantial size relative to the freelyopen and excess fuel passageways to reduce the pressure of said excessfuel delivered to said chamber, said chamber being in communication withthe first said passageway whereby said excess fuel is delivered atreduced pressure to said bore during said suction stroke, and a controlvalve operatively disposed between said chamber and said excess fuelpassageway for regulating communication therebetween, said excess fuelpassageway extending perpendicularly away from said fuel deliverypassageway, said body being provided with a further chamber and furtherpassage connecting the excess fuel passageway to the first said chamber,said control valve being located in said further chamber, said furtherpassage being parallel to said fuel delivery passageway.

2. A fuel injection pump for a diesel engine comprising a pump body, abarrel supported in Said body, said barrel being provided with a bore, aplunger sliclably supported in said bore for providing suction andcompression strokes in said bore, a freely open passageway beingprovided in the wall of said barrel at a location at which the plungerpasses beyond said passageway during said suction stroke to open saidpassageway while during said compression stroke the plunger closes saidpassageway, said passageway being in communication with said bore forpermitting fuel to flow into said bore during the suction stroke of saidplunger, said pump body being provided with a fuel delivery passagewaywhich extends from said bore, valve means in the fuel deliverypassageway for controlling discharge of fuel from said fuel deliverypassageway, said plunger, during said compression stroke, exertingpressure on fuel in said bore and said fuel delivery passage to opensaid valve means to permit discharge of said fuel from said fueldelivery passageway, said body being provided with an excess fuelpassageway coupled to said fuel delivery passageway and with a charnberin communication with said excess fuel passageway to permit excess fuelin said fuel delivery passageway to be delivered to Said chamber, saidbody being provided with a fuel inlet passageway opening into saidchamber, said chamber being of substantial size relative to the freelyopen and excess fuel passageways to reduce the pressure of said excessfuel delivered to said chamber, said chamber being in communication withthe first said passageway whereby said excess fuel is delivered atreduced pressure to said bore during said suction stroke, and a controlvalve operatively disposed between said chamber and said excess fuelpassageway for regulating communication therebetween, said excess fuelpassageway extending perpendicularly away from said fuel deliverypassageway, said body being provided with a further chamber and furtherpassage connecting the excess fuel passageway to the first said chamber,said control valve being located in said further chamber, said furtherpassage being parallel to said fuel delivery passageway, the rst saidchamber being coaxial with said further passage and of substantiallygreater diameter than the same, said fuel inlet passageway extendingperpendicularly into the rst said chamber.

3. A fuel injection pump for a diesel engine comprising a pump body, abarrel supported in said body, said barrel being provided with a bore, aplunger slidably supported in said bore for providing suction andcompression strokes in said bore, a freely open passageway beingprovided in the wall of said barrel at a location at which the plungerpasses beyond said passageway during said suction stroke to open saidpassageway while during said compression stroke the plunger closes saidpassageway, said passageway being in communication with said bore forpermitting fuel to flow into said bore during the suction stroke of saidplunger, said pump body being provided with a fuel delivery passagewaywhich extends from said bore, valve means in the fuel deliverypassageway for controlling discharge of fuel from said fuel deliverypassageway, said plunger, during said compression stroke, exertingpressure on fuel in said bore and said fuel delivery passage to opensaid valve means to permit discharge of said fuel from said fueldelivery passageway, said body being provided with an excess fuelpassageway coupled to said fuel delivery passageway and with a chamberin communication with said excess fuel passageway to permit excess fuelin said fuel delivery passageway to be delivered to said chamber, saidbody being provided with a fuel inlet passageway opening into saidchamber, said chamber being of substantial size relative to the freelyopen and excess fuel passageways to reduce the pressure of said excessfuel delivered to said chamber, said chamber being in communication withthe first said passageway whereby said excess fuel is delivered atreduced pressure to said bore during said suction stroke, and a controlvalve operatively disposed between said chamber and said excess fuelpassageway for regulating 5 6 communication therebetween, said excessfuel passageway said chamber, said body being further provided with anextending perpendicularly away from said fuel delivery inclined passageextending between the first said chamber passageway, said body beingprovided with a further and said freely open passageway. chamber andfurther passage connecting the excess fuel passageway to the rst saidchamber, said control valve 5 References Cited II the le 0f this Patentbeing located in said further chamber, said further passage UNITEDSTATES PATENTS| being parallel to said fuel delivery passageway, the rstsaid chamber being coaxial with said further passage and 2,130,521Brunner Sept. 20, 1938 of substantially greater diameter than the same,said fuel 2,697,401 Barberena Dec. 21, 1954 inlet passageway extendingperpendicularly into the rst 10 2,880,675 Bessiere Apr. V7, 1959 UNITEDSTATES PATENT OFFICE CERTIFICATE OE CORRECTION Patent Noa 3KI 13(9830July 7g 1964 Toshi Umezawa It is hereby certified that error appears inthe above numbered patent requiring correction and that the said LettersPatent should read as corrected below.

In the gTant lines I and I2g n the heading to the printed speejeationuline 3v for "Tosho Umezawau each oeeurreneel read Tosh Umezawa e-g inthe sheet of drawingU line IU :for TOSHIO UMEZAWA" read TOSHI UMEZAWA NoSigned and sealed this 24th day of November l94 (SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER AltestingOfficer

1. A FUEL INJECTION PUMP FOR A DIESEL ENGINE COMPRISING A PUMP BODY, ABARREL SUPPORTED IN SAID BODY, SAID BARREL BEING PROVIDED WITH A BORE, APLUNGER SLIDABLY SUPPORTED IN SAID BORE FOR PROVIDING SUCTION ANDCOMPRESSION STROKES IN SAID BORE, A FREELY OPEN PASSAGEWAY BEINGPROVIDED IN THE WALL OF SAID BARREL AT A LOCATION AT WHICH THE PLUNGERPASSES BEYOND SAID PASSAGEWAY DURING SAID SUCTION STROKE TO OPEN SAIDPASSAGEWAY WHILE DURING SAID COMPRESSION STROKE THE PLUNGER CLOSES SAIDPASSAGEWAY, SAID PASSAGEWAY BEING IN COMMUNICATION WITH SAID BORE FORPERMITTING FUEL TO FLOW INTO SAID BORE DURING THE SUCTION STROKE OF SAIDPLUNGER, SAID PUMP BODY BEING PROVIDED WITH A FUEL DELIVERY PASSAGEWAYWHICH EXTENDS FROM SAID BORE, VALVE MEANS IN THE FUEL DELIVERYPASSAGEWAY FOR CONTROLLING DISCHARGE OF FUEL FROM SAID FUEL DELIVERYPASSAGEWAY, SAID PLUNGER, DURING SAID COMPRESSION STROKE, EXERTINGPRESSURE ON FUEL IN SAID BORE AND SAID FUEL DELIVERY PASSAGE TO OPENSAID VALVE MEANS TO PERMIT DISCHARGE OF SAID FUEL FROM SAID FUELDELIVERY PASSAGEWAY, SAID BODY BEING PROVIDED WITH AN EXCESS FUELPASSAGEWAY COUPLED TO SAID FUEL DELIVERY PASSAGEWAY AND WITH A CHAMBERIN COMMUNICATION WITH SAID EXCESS FUEL PASSAGEWAY TO PERMIT EXCESS FUELIN SAID FUEL DELIVERY PASSAGEWAY TO BE DELIVERED TO SAID CHAMBER, SAIDBODY BEING PROVIDED WITH A FUEL INLET PASSAGEWAY OPENING INTO SAIDCHAMBER, SAID CHAMBER BEING OF SUBSTANTIAL SIZE RELATIVE TO THE FREELYOPEN AND EXCESS FUEL PASSAGEWAYS TO REDUCE THE PRESSURE OF SAID EXCESSFUEL DELIVERED TO SAID CHAMBER, SAID CHAMBER BEING IN COMMUNICATION WITHTHE FIRST SAID PASSAGEWAY WHEREBY SAID EXCESS FUEL IS DELIVERED ATREDUCED PRESSURE TO SAID BORE DURING SAID SUCTION STROKE, AND A CONTROLVALVE OPERATIVELY DISPOSED BETWEEN SAID CHAMBER AND SAID EXCESS FUELPASSAGEWAY FOR REGULATING COMMUNICATION THEREBETWEEN, SAID EXCESS FUELPASSAGEWAY EXTENDING PERPENDICULARLY AWAY FROM SAID FUEL DELIVERYPASSAGEWAY, SAID BODY BEING PROVIDED WITH A FURTHER CHAMBER AND FURTHERPASSAGE CONNECTING THE EXCESS FUEL PASSAGEWAY TO THE FIRST SAID CHAMBER,SAID CONTROL VALVE BEING LOCATED IN SAID FURTHER CHAMBER, SAID FURTHERPASSAGE BEING PARALLEL TO SAID FUEL DELIVERY PASSAGEWAY.